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Global climate change and overgrazing are driving shifts in the plant composition of grassland communities, which may profoundly affect the function of grassland ecosystems in regulating runoff and soil erosion. Here, we examined the shift effects of normal hillslope alpine meadow to shrub and severely degraded meadow states on runoff and sediment generation under natural rainfall conditions, and determined the contributions of plant and soil properties changes to soil erodibility, runoff and sediment generation by in situ rainfall experiment and monitoring on the hillslope of Qinghai-Tibetan Plateau. The results showed that normal meadow shift into severely degraded meadow state, mean weight diameter, soil saturated hydraulic conductivity, soil cohesion and soil erodibility K-factor at the topsoil decreased by 70.3%, 73.1%, 80.3% and −13.1%, respectively, and when normal meadows shift into shrub meadow state, they reduced by 49.1%, −1.3%, 49.4%, and −8.3%, respectively. Runoff and soil loss significantly changed by - 40.0% and 177.8% when normal meadow shifted into a severely degraded meadow state, while runoff and soil loss significantly changed by + 65.0% and +77.8% when normal meadow shifted into a shrub meadow state. Our findings highlight that the two divergent shifts both increased soil loss compared to the normal hillslope alpine meadows. Overall, our results indicate that the divergent shifts of normal alpine meadows exacerbated soil erodibility and soil loss of hillslope alpine meadows. These results obtained here offer a novel perspective on the regulation of runoff and soil erosion in the alpine meadow ecosystem.

Abstract Grasslands are an important component of terrestrial ecosystems that play a crucial role in the carbon cycle and climate change. In this study, we collected aboveground biomass (AGB) data from 223 grassland quadrats distributed across the Loess Plateau from 2011 to 2013 and predicted the spatial distribution of the grassland AGB at a 100-m resolution from both meteorological station and remote sensing data (TM and MODIS) using a Random Forest (RF) algorithm. The results showed that the predicted grassland AGB on the Loess Plateau decreased from east to west. Vegetation indexes were positively correlated with grassland AGB, and the normalized difference vegetation index (NDVI) acquired from TM data was the most important predictive factor. Tussock and shrub tussock had the highest AGB, and desert steppe had the lowest. Rainfall higher than 400 m might have benefitted the grassland AGB. Compared with those obtained for the bagging, mboost and the support vector machine (SVM) models, higher values for the mean Pearson coefficient (R) and the symmetric index of agreement (λ) were obtained for the RF model, indicating that this RF model could reasonably estimate the grassland AGB (65.01%) on the Loess Plateau.

BACKGROUND: Insulin resistance contributes to the cardio-metabolic risk. The effect of leptin in obese and overweight population on insulin resistance was seldom reported. METHODS: A total of 1234 subjects (572 men and 662 women) aged ≥18 y was sampled by the procedure. Adiposity measures included BMI, waist circumference, hip circumference, WHR, upper arm circumference, triceps skinfold and body fat percentage. Serum leptin concentrations were measured by an ELISA method. The homeostasis model (HOMA-IR) was applied to estimate insulin resistance. RESULTS: In men, BMI was the variable which was most strongly correlated with leptin, whereas triceps skinfold was most sensitive for women. More importantly, serum leptin levels among insulin resistant subjects were almost double compared to the subjects who had normal insulin sensitivity at the same level of adiposity in both men and women, after controlling for potential confounders. In addition, HOMA-IR increased significantly across leptin quintiles after adjustment for age, BMI, total energy intake, physical activity and smoking status in both men and women (p for trend

The establishment of grasslands on abandoned cropland has been proposed as an effective method to mitigate climate change. In this study, five cultivated grasslands (three leguminous species and two gramineous species), one abandoned cropland, and one natural grassland were studied to examine how soil organic carbon (SOC) sequestration rate and sequestration efficiency change in a semi-arid area in China. Our results showed that leguminous grasslands had greater total biomass (above-and belowground biomass), SOC storage, SOC sequestration rate, and efficiency than gramineous grasslands, abandoned cropland, and natural grassland during the experimental period. The largest soil carbon (C) accumulation in leguminous grassland was mainly attributed to the capacity to incorporate C and the higher biomass production. Leguminous grasslands accumulated more SOC than gramineous grasslands by 0.64MgC ha-1 yr-1. The average SOC sequestration efficiency in leguminous grassland (1.00) was about 2 times greater than gramineous grassland (0.34). The results indicate that cultivated leguminous grassland sequestered more SOC with higher SOC sequestration efficiency than cultivated gramineous grassland in arid and semi-arid areas. Our results provide a reference for ecological management in arid and semi-arid areas. [ABSTRACT FROM AUTHOR]

With the development of power systems in recent years, the total amount of power cables in operation has increased greatly, and there are growing reports of cable failure. Cable failures may be due to various intrinsic or extrinsic factors and can lead to massive economic loss. With regard to high-voltage cables, such as 110 kV power cables, there are very few accurate reports on the actual fault observed. This article first analyses the possible causes of power cable outer sheath failure. It then introduces the bridge and step voltage methods, which are traditionally used for cable fault locating, and describes a new method for accurate fault locating in 110 kV cables, which uses the bridge method to pre-locate the fault and then the step voltage method to accurately determine the precise fault locating. Field testing confirms the applicability of the new method for accurate fault locating in 110 kV power cables. The results shown in this article may provide a good reference for the development of future research in related fields. [ABSTRACT FROM AUTHOR]

Gas insulated switchgear (GIS) is an important electric power equipment in a substation, and its running state has a significant relationship with stability, security, and reliability of the whole electric power system. Detecting and analyzing the decomposition byproducts of sulfur hexafluoride gas (SF6) is an effective method for GIS state assessment and fault diagnosis. This paper proposes a novel gas sensor based on flower-like ZnO nanorods to detect typical SF6 decompositions. Flower-like ZnO nanoparticles were synthesized via a simple hydrothermal method and characterized by X-ray powder diffraction and field-emission scanning electron microscopy, respectively. The gas sensor was fabricated with a planar-type structure and applied to detect SF6 decomposition products. It shows excellent sensing properties to SO2, SOF2, and SO2F2 with rapid response and recovery time and long-term stability and repeatability. Moreover, the sensor shows a remarkable discrimination among SO2, SOF2, and SO2F2 with high linearity, which makes the prepared sensor a good candidate and a wide application prospect detecting SF6 decomposition products in the future. [ABSTRACT FROM AUTHOR]

To mitigate the impacts of grassland degradation on the Qinghai–Tibetan Plateau (QTP), in recent decades China has been implementing large-scale conservation programs and has invested about 42 billion CNY (7 billion USD). However, these programs are faced with major challenges involving trade-offs between ecological function, livestock production and income of pastoralists. Scientific assessments, as well as technical and policy issues, have not fully captured the complex ecological, social and economic dynamics of the challenges facing grassland management on the QTP. Pastoral livestock production on the QTP is characterized by imbalance in both quality and quantity between livestock seasonal nutrient requirements and herbage production, which forces pastoralists to keep larger numbers of livestock for longer periods, leading to overgrazing. To solve these problems, an integrated crop-livestock system is promoted to improve the efficiency of livestock production and conserve natural grassland as well for a sustainable system for the QTP.